umbonate

[ uhm-buh-nit, -neyt ]

/ ˈʌm bə nɪt, -ˌneɪt /

having an umbo or projecting boss.

shaped like an umbo; having a rounded convex form: an umbonate fungus.

Origin of umbonate

1820–30; < Latin umbōn- (stem of umbō; see umbo) + -ate¹

sub·um·bo·nate, adjective

When the center of the pileus is raised in the form of a boss or knob it is umbonate (Fig. 242).

Studies of American Fungi. Mushrooms, Edible, Poisonous, etc. |George Francis Atkinson
The umbonate pileus and the nearly free, broad, gray gills will distinguish it.

The Mushroom, Edible and Otherwise |M. E. Hard
This species differs from C. atrata in having an umbonate pileus.

The Mushroom, Edible and Otherwise |M. E. Hard
It may be rounded and depressed (concave), elevated (convex), level (plane), or with a little mound in the centre (umbonate).

Among the Mushrooms |Ellen M. Dallas and Caroline A. Burgin

The pileus is often umbonate or gibbous, and the center is often darker than the margin.

Studies of American Fungi. Mushrooms, Edible, Poisonous, etc. |George Francis Atkinson